Institute of Food and Agricultural Technology-CIDSAV-XaRTA, University of Girona, 17071 Girona, Spain.
Appl Environ Microbiol. 2011 May;77(10):3174-81. doi: 10.1128/AEM.02760-10. Epub 2011 Mar 25.
The efficacy of Pseudomonas fluorescens EPS62e in the biocontrol of Erwinia amylovora was improved by a procedure of physiological adaptation to increase colonization and survival in the phytosphere of rosaceous plants. The procedure consisted of osmoadaptation (OA) and nutritional enhancement (NE). OA was based on saline stress and osmolyte amendment of the growth medium during inoculum preparation. NE consisted of addition of glycine and Tween 80 to the formulation. NE and OA increased the growth rate and carrying capacity of EPS62e under high-relative-humidity (RH) conditions and improved survival at low RH on flowers under controlled environmental conditions. NE did not promote growth or affect infection capacity of E. amylovora. The effect of both methods was tested in the field by following the population of EPS62e using quantitative PCR (Q-PCR) (total population) and CFU counting (culturable population) methods. Following field application, EPS62e colonized blossoms, but it was stressed, as indicated by a sharp decrease in culturable compared to total population levels. However, once established in flowers and at the end of bloom, almost all the total population was culturable. The physiological adaptation treatments increased population levels of EPS62e over those of nonadapted cells during the late stage of the flowering period. Control of fire blight infections in flowers and immature fruits was tested by field application of EPS62e and subsequent inoculation with E. amylovora under controlled-environment conditions. The efficacy of fire blight control increased significantly with the combination of nutritional enhancement and osmoadaptation, in comparison with the absence of physiological adaptation.
通过一种生理适应程序来提高荧光假单胞菌 EPS62e 对仁果细菌性溃疡病的生物防治效果，该程序包括适应渗透压（OA）和营养增强（NE）。OA 基于接种物制备过程中的盐胁迫和渗透剂对生长培养基的改良。NE 由向配方中添加甘氨酸和吐温 80 组成。NE 和 OA 提高了 EPS62e 在高相对湿度（RH）条件下的生长速度和承载能力，并改善了在受控环境条件下花朵中低 RH 下的生存能力。NE 不会促进仁果细菌性溃疡病的生长或影响其感染能力。通过使用定量 PCR（Q-PCR）（总种群）和 CFU 计数（可培养种群）方法跟踪 EPS62e 的种群，在田间测试了这两种方法的效果。田间应用后，EPS62e 定植在花朵上，但由于可培养与总种群水平相比急剧下降，因此受到压力。然而，一旦在花朵中建立并在开花期末期，几乎所有的总种群都可培养。生理适应处理在开花后期增加了 EPS62e 的种群水平，超过了未适应细胞的种群水平。通过在受控环境条件下田间应用 EPS62e 并随后接种仁果细菌性溃疡病，测试了对花朵和未成熟果实中细菌性溃疡病感染的控制效果。与不进行生理适应相比，营养增强和渗透压适应的结合显著提高了控制细菌性溃疡病的效果。
